Category Archives: Php

Detect mobile browsers in server-side code

Last week I found myself needing to detect mobile browsers on the server-side and ran across this extremely useful site:

http://detectmobilebrowsers.com/

It offers open source code for doing just that. Many languages are available: C#, Ruby, JavaScript & node.js, PHP, Python, and more. Even Perl!

Often you’d use this code to redirect the user to a mobile version of your site. However, my site uses the responsive Twenty Twelve WordPress theme. This works well on mobile browsers. Thus, I don’t really want or need to redirect the user.

Unfortunately, there’s one particular piece of content that was banjaxxing the page width on mobile devices. It needed to be replaced. Normally I’d do this on the client-side, which is what the theme does. In this cases the content’s Ts & Cs meant I wasn’t allowed to. But I could do it on the server.

You probably know that you can’t get the client’s screen resolution or browser window dimensions on the server. However, you can use the user-agent string to detect mobile browsers. This is exactly what the code at detectmobilebrowsers.com does. They’ve written and tested code that will reliably detect mobile browsers across most devices. That isn’t something I wanted to attempt myself (how would I test it?), and neither should you.

WordPress runs on PHP so I now have this particularly minging, but highly functional, lump of code in one of my template scripts:

<?php
$useragent=$_SERVER['HTTP_USER_AGENT'];
if(preg_match('/(android|bb\d+|meego).+mobile|avantgo|bada\/|blackberry|blazer|compal|elaine|fennec|hiptop|iemobile|ip(hone|od)|iris|kindle|lge |maemo|midp|mmp|mobile.+firefox|netfront|opera m(ob|in)i|palm( os)?|phone|p(ixi|re)\/|plucker|pocket|psp|series(4|6)0|symbian|treo|up\.(browser|link)|vodafone|wap|windows (ce|phone)|xda|xiino/i',$useragent)||preg_match('/1207|6310|6590|3gso|4thp|50[1-6]i|770s|802s|a wa|abac|ac(er|oo|s\-)|ai(ko|rn)|al(av|ca|co)|amoi|an(ex|ny|yw)|aptu|ar(ch|go)|as(te|us)|attw|au(di|\-m|r |s )|avan|be(ck|ll|nq)|bi(lb|rd)|bl(ac|az)|br(e|v)w|bumb|bw\-(n|u)|c55\/|capi|ccwa|cdm\-|cell|chtm|cldc|cmd\-|co(mp|nd)|craw|da(it|ll|ng)|dbte|dc\-s|devi|dica|dmob|do(c|p)o|ds(12|\-d)|el(49|ai)|em(l2|ul)|er(ic|k0)|esl8|ez([4-7]0|os|wa|ze)|fetc|fly(\-|_)|g1 u|g560|gene|gf\-5|g\-mo|go(\.w|od)|gr(ad|un)|haie|hcit|hd\-(m|p|t)|hei\-|hi(pt|ta)|hp( i|ip)|hs\-c|ht(c(\-| |_|a|g|p|s|t)|tp)|hu(aw|tc)|i\-(20|go|ma)|i230|iac( |\-|\/)|ibro|idea|ig01|ikom|im1k|inno|ipaq|iris|ja(t|v)a|jbro|jemu|jigs|kddi|keji|kgt( |\/)|klon|kpt |kwc\-|kyo(c|k)|le(no|xi)|lg( g|\/(k|l|u)|50|54|\-[a-w])|libw|lynx|m1\-w|m3ga|m50\/|ma(te|ui|xo)|mc(01|21|ca)|m\-cr|me(rc|ri)|mi(o8|oa|ts)|mmef|mo(01|02|bi|de|do|t(\-| |o|v)|zz)|mt(50|p1|v )|mwbp|mywa|n10[0-2]|n20[2-3]|n30(0|2)|n50(0|2|5)|n7(0(0|1)|10)|ne((c|m)\-|on|tf|wf|wg|wt)|nok(6|i)|nzph|o2im|op(ti|wv)|oran|owg1|p800|pan(a|d|t)|pdxg|pg(13|\-([1-8]|c))|phil|pire|pl(ay|uc)|pn\-2|po(ck|rt|se)|prox|psio|pt\-g|qa\-a|qc(07|12|21|32|60|\-[2-7]|i\-)|qtek|r380|r600|raks|rim9|ro(ve|zo)|s55\/|sa(ge|ma|mm|ms|ny|va)|sc(01|h\-|oo|p\-)|sdk\/|se(c(\-|0|1)|47|mc|nd|ri)|sgh\-|shar|sie(\-|m)|sk\-0|sl(45|id)|sm(al|ar|b3|it|t5)|so(ft|ny)|sp(01|h\-|v\-|v )|sy(01|mb)|t2(18|50)|t6(00|10|18)|ta(gt|lk)|tcl\-|tdg\-|tel(i|m)|tim\-|t\-mo|to(pl|sh)|ts(70|m\-|m3|m5)|tx\-9|up(\.b|g1|si)|utst|v400|v750|veri|vi(rg|te)|vk(40|5[0-3]|\-v)|vm40|voda|vulc|vx(52|53|60|61|70|80|81|83|85|98)|w3c(\-| )|webc|whit|wi(g |nc|nw)|wmlb|wonu|x700|yas\-|your|zeto|zte\-/i',substr($useragent,0,4))) : ?>

    <div style="padding-bottom: 16px; margin-left: -24px; margin-top: -24px;">
        <!-- Content displayed on mobile (but not tablet) browsers here -->
    </div>

<?php else : ?>

    <span style="float: right; clear: right; padding-bottom: 8px;">
        <!-- Content displayed on all other browsers here -->
    </span>

<?php endif; ?>

DO NOT copy this code. New devices are being released all the time so make sure you grab the latest version from detectmobilebrowsers.com. That way your code will work with the most recent generation of devices.

To edit your WordPress templates just open up your dashboard and click Appearance > Editor:

Edit WordPress templates.

(Oh, and if I ever need that check in more than one place I’ll refactor it into a method. For now I can live with it sitting in the one template where I need it.)

As my comment in the code suggests, this won’t work for tablets. If you need special support for them, add the code snippet under the Tablets section here to the first regex. You can also separate the checks for mobiles and tablets, or even different models of mobile/tablet, if you need more fine-grained control over site behaviour.